Composite propeller blade structure

Abstract

A composite propeller blade structure includes at least a rotation shaft and a rotation surface on which plural blades are formed, and characterized in that: each of the blades is composed of plural blade units; and in the equivalent radius cross section of each of the blades, the installed location of a front edge of the blade unit at the downstream is defined as following: in the rotation axial direction, which is located behind a rear edge of the adjacent blade unit at the upstream, and the maximum distance thereof is not greater than 25% of the radius of the adjacent blade unit at the upstream; and in the circumferential direction, located at the pressure surface side defined on the nose-trail line of the adjacent blade unit at the upstream, and the maximum range thereof is not greater than (360°/2N), wherein N is the quantity of the blades.

What is claimed is: 
     
         1 . A composite propeller blade structure, including:
 at least a rotation shaft and a rotation surface correspondingly formed relative to the rotation shaft; and   a plurality of blades formed on the rotation surface, each of the blades being composed of a plurality of blade units,   wherein a distance between any two adjacent blades is greater than a distance between any two adjacent blade units, and a suction side of the blade unit at downstream is located in the position closer to a pressure side of the blade unit at upstream rather than the suction side of the blade unit at the upstream. Accordingly, in an equivalent radius cross section of each of the blades, a installed location of a front edge of the blade unit at the downstream is defined as following: in a rotation axial direction, which is located behind a rear edge of an adjacent blade unit at the upstream, and a maximum distance defined in the rotation axial direction and between the front edge of the blade unit at the downstream and the rear edge of the adjacent blade unit at the upstream is not greater than 25% of the radius of the adjacent blade unit at the upstream; and in a circumferential direction, a installed location of the front edge of the blade unit at the downstream is located at the pressure surface side defined on a nose-trail line of the adjacent blade unit at the upstream, and a maximum range defined in circumferential direction and between the front edge of the blade unit at the downstream and the nose-tail line of the adjacent blade unit at the upstream is not greater than 360°/2N, wherein N is the quantity of the blades.   
     
     
         2 . The composite propeller blade structure according to  claim 1 , wherein in any of the blades, an area formed on the smallest blade unit is larger than 50% of an area formed on the biggest blade unit. 
     
     
         3 . The composite propeller blade structure according to  claim 1 , wherein in any of the blades, a radius formed on the smallest blade unit is larger than 60% of a radius formed on the biggest blade unit. 
     
     
         4 . The composite propeller blade structure according to  claim 1 , wherein in any of the blades, a strengthening structure is installed for connecting the adjacent blade units. 
     
     
         5 . The composite propeller blade structure according to  claim 1 , wherein each of the blades is composed of two blade units. 
     
     
         6 . The composite propeller blade structure according to  claim 1 , wherein each of the blades is composed of three blade units. 
     
     
         7 . The composite propeller blade structure according to  claim 1 , wherein the blades are formed with the same configuration.